Ginger evolved in South-east Asia but is never found in the wild sate. It has been used as a spice and medicine in India and China since ancient times; it was known to the Greeks and Romans and generally throughout Europe by the tenth century. Today it can be found in cultivation in most tropical countries: Jamaica, India, Nigeria, Sierra Leone, Australia, and China are well known sources.
Ginger is a perennial herb 30-100 cm (3 ft) in height, with an underground stem (rhizome) with swollen segments. The aerial stem has narrow, sword-shaped leaves. Flowers are rarely seen but, if preset, are yellowish or greenish white.
The rhizome, often erroneously referred to as the root, is the part used.
The plant is of great importance as a spice or flavoring agent, being included in biscuits, puddings, cakes, ginger-bread, soups, pickles, curry powder, ginger beer, ginger ale, and ginger wine. For these purposes, the rhizome itself may be utilized, or its essential oil or its oleoresin, a solvent extraction of the rhizome, which contains other substances in addition to the oil.
Ginger has had many uses in herbal medicine. It is said to be carminative and has been used for hundreds of years to treat gastrointestinal distress. It is also employed as an antipyretic, diuretic, diaphoretic, and antitussive (stops coughing) – these properties would explain its use for colds and influenza. It is claimed that ginger stimulates the circulation and helps blood flow to the surface, useful for chilblains and poor circulation to the hands and feet.
There have been a considerable number of animal and human experiments into the therapeutic value of ginger. Many of its traditional uses have been supported. Essential oil and gingerols and their derivatives (shogaols) present in the oleoresin are regarded as the active principles.
Some animal experiments indicate that ginger shows cardiotonic activity (favorable action on the heart). The essential oil has been demonstrated as antibacterial, at least in vitro.
There has been considerable interest in ginger as an agent for calming travel or motion sickness. Some human studies support this use, but not all.
In Germany, it has been recommended as a treatment for dyspepsia and motion sickness.
Excessive doses should be avoided during pregnancy and lactation, and by those suffering from, e.g. cardiac or diabetic conditions.